DRAW-PROCESSING OF CAN BODIES

Abstract: Draw processing flat-rolled sheet metal substrate preselectively precoated on each surface with organic and draw lubricant into one-piece can bodies ready for assembly into sanitary can packs. Cupping of precoated flat-rolled sheet metal can stock using preselected tooling configurations and clearance avoids any increase in side wall metal thickness gage. Tension elongation during redraw is controlled over side wall height by clamping solely between planar clamping surfaces. High production rate blanking and cupping (36) is achieved with out-of-phase simultaneous movement of cupping die and punch which provides for rapid discharge of cup-shaped work product (37), open-end-down on flange (41) at open end of cup. Surface area of the cavity entrance zone for each die is fabricated about multiple radii forming sharp edge about which coated can stock is drawn into each die cavity.

Description: "DRAW-PROCESSING OF CAN BODIES" Related Applications This application is a continuation-in-part of copending co-owned applications: U.S. Application Serial No. 07/596,854 entitled FABRICATING ONE-PIECE CAN BODIES WITH CONTROLLED SIDE WALL ELONGATION, filed October 12, 1990; U.S. Application Serial No. 07/866,661 entitled ONE- PIECE DRAW PROCESS CAN BODIES, filed April 8, 1992 as a division of U.S. Application Serial No. 07/573,548, filed August 27, 1990, now U.S. Patent #5,114,657 granted 06/09/92; U.S. Application Serial No. 08/014,263 entitled DRAWN CAN BODY METHODS, APPARATUS AND PRODUCTS, filed February 5, 1993 as a division of U.S. Application Serial No. 06/831,624 entitled METHOD AND APPARATUS FOR DRAWING SHEET METAL CAN STOCK (as amended), filed February 21, 1986, now U.S. Patent #5,014,536 granted 05/14/91, which was a continuation-in-part of U.S. Application Serial No. 06/712,238 entitled DRAWN CAN BODY METHODS, APPARATUS AND PRODUCTS, filed on March 15, 1985 (now abandoned); and U.S. Application Serial No. 08/053,458 entitled DRAW- PROCESS METHODS, SYSTEMS AND TOOLING FOR FABRICATING ONE- PIECE CAN BODIES, filed April 27, 1993 as a division of U.S. Application Serial No. 07/490,781 entitled DRAW- PROCESS METHODS, SYSTEMS AND TOOLING FOR FABRICATING ONE- PIECE CAN BODIES, filed March 8, 1990, now U.S. Patent #5,209,099. This invention relates to new draw-process fabricating methods and apparatus for improved production of new sanitary-pack can bodies from can stock comprising flat-rolled sheet metal substrate precoated with organic coating and draw lubricant. In particular, this invention is concerned with draw-processing substantially-uniform side wall thickness can bodies for sanitary can packs from such can stock free of any side wall ironing step. A contribution of the new draw-processing teachings being presented is the capability of maintaining the integrity of the organic polymeric coating, as precoated on flat-rolled sheet metal, during shaping of a cup-shaped work product and reshaping into cylindrical configuration one-piece can bodies. The draw-processing fabrication is isolated from the flat sheet metal coating and treatment processing; the draw-processed can bodies do not require treatment during processing and are ready as fabricated for use in sanitary can packs for comestibles without application of organic coating or adding of any organic coating for coating repair purposes. A significant commercial contribution is the decrease in sheet metal costs for sanitary-pack can bodies. The prior art conventional draw-redraw practice increases side wall metal thickness above strength requirements for sanitary can packs. In that conventional draw-redraw practice,thickening of the side wall increases progressively in approaching the open end of a one-piece sheet metal can body. And, when side wall ironing is resorted to in an attempt to overcome that side wall thickening problem, heavier gage starting material must be used from the start of the drawing and ironing process. As a result, the gage of the bottom wall metal in the drawn and ironed can body can significantly exceed that normally required for sanitary can pack strength purposes, and organic coating facilities have been required after drawing and ironing. Present teachings significantly decrease sheet metal costs by decreasing blank cut edge diameter requirements in relation to conventional draw-redraw requirements; and, also, enable more uniform gage decrease of side wall metal during draw-processing fabrication of precoated can stock. The can body of the invention is fabricated with flange metal at its open end from lighter-weight precoated can stock which is able to meet sanitary pack strength requirements, and is ready for sanitary can packs as fabricated eliminating post-fabrication organic coating or organic coating repair facilities. Precoated work- hardened flat-rolled steel is a preferred embodiment for economically achieving the above objective. For purposes of more detailed description of new blanking and cupping press means, specific embodiments of new draw-processing steps with improved, more uniform side wall tension control and new one-piece can bodies for sanitary can packs, reference is made to the accompanying drawings, in which: FIG. l is a diagrammatic general-arrangement presentation for describing specific draw-processing steps and sequencing of the invention for improved in-line fabrication of new precoated one-piece can bodies; FIGS. 2-8 are schematic cross-sectional partial views of blanking and cupping and tooling with locations at selected sequential cycle times for describing blanking and cupping methods and offset relative movement of tooling in accordance with the invention; FIGS. 9-13 present a schematic arrangement of interrelated partial views of cupping press means for describing rotary (360°) crankshaft operation with separate connector arm means for providing out-of-phase relative movement of separate drive means for the cupping die and separate drive means for the cupping punch, in accordance with the invention; FIGS. 14-17 are enlarged cross-sectional partial views for describing reshaping, in preparation for redraw, of the curved-surface unitary juncture between endwall and side wall of the drawn cup-shaped work product of FIGS. 2- 8; FIG. 18 is a presentation for describing the geometry in manufacture of the multiple-radius curved-surface transition zone between a planar clamping surface and cylindrical side wall shown in FIGS. 11-14; FIGS. 19-20 are schematic, cross-sectional partial views for describing another embodiment of a multiple- radius curved-surface transition zone as used between a near cylindrical internal wall of die cavity and the planar clamping surface circumscribing such entrance zone for a cupping die, or for a redraw die of the invention; FIGS. 22-24 are enlarged cross-sectional partial views of tooling and cup-shaped work product for describing the improved diameter reduction and control of side wall tension during redraw-processing of the work product, in accordance with the invention, after reshaping of the unitary junction as described in relation to FIGS. 11-14; and FIGS. 25-26 are cross-sectional partial views of endwall profiling tooling and can body with final redraw endwall profiling. In accordance with the invention, planar can stock comprising flat-rolled sheet metal precoated with organic polymeric coating and draw-processing lubricant is shaped into a cup-shaped work product with flange metal at its open end. The cup-shaped shallow-depth work product is then reshaped by draw-processing into a precoated cylindrical-configuration one-piece can body. Precoated flat-rolled sheet metal from a cut planar blank is shaped into the cup shape with endwall, side wall, and flange metal at the open end of the one-piece work product. A small diameter one-piece can body is then formed, adding height substantially uniformly decreasing side wall thickness under tension, while maintaining an upper end flange. In draw-processing to form cylindrical one-piece can bodies, planar metal is converted into curvilinear side wall metal and draw-processing always involves a decrease in diameter in order to form or increase side wall height. However, cold-forging side wall metal of a cup-shaped work product in order to increase side wall height involves working of only side wall metal, a process step referred to as side wall ironing in the canmaking industry. Such an ironing step does not involve conversion of planar metal into curvilinear side wall metal; nor does it change the container diameter. Fabricating one-piece can bodies by prior art draw- redraw practice increases the thickness gage of the side wall metal in approaching the open end of the can body as the flat-rolled metal is reshaped into a cylindrical cup. The present invention eliminates such thickening of side wall metal by improved tooling configuration and clamping practice. The side wall metal of the drawn cup is then decreased uniformly by improved tension control during draw and redraw-processing of can bodies with flange metal for use in cylindrical sanitary can packs. In two-step processing of the invention, can body diameter exceeds can body side wall height; and a three-step process produces can bodies for sanitary can packs, for example condensed soup cans, where side wall height can exceed can body diameter. Referring to the general arrangement diagrammatic presentation of FIG. 1, a travel path 30 is established at the entrance to fabrication line 32 for precoated can stock. Fabricated flat-rolled sheet metal is prepared to predetermined gage and surface preparation at station 33 and precoated with organic polymeric coating and draw lubricant at station 34. Determining adequacy of lubrication augmenting and whether surface lubrication is required is carried out at station 35. The invention avoids thickening of side wall substrate during forming of a cup-shaped work product. And, as the work product diameter is decreased in a single redraw operation or double redraw operations, an improved tension control is exercised in the side wall to provide uniform substrate thickness gage throughout side wall height between a closed endwall juncture and open-end flange metal. Solely planar clamping contributes to uniform control of side wall tension throughout the new draw-processing steps; and the entire procession of the invention is entirely free of any ironing step. Improved metal economy for draw-processed organic polymeric-coated can bodies is a commercially significant contribution as is sheet metal preparation (33) and precoating of can stock (34) independently of the fabricating line. Draw-processing is carried out without any treatment of the can stock or can body required prior to canning. In the blanking phase of a new blanking and cupping press means 36 (FIG. 1) , a blank of preselected diameter is cut from precoated flat-rolled can stock. Then, a cup- shaped work product 40 is formed and discharged directly onto the fabricating line travel path, open-end-down. The invention teaches that the bulk of the gross diameter reduction, that is the decrease from cut blank diameter to final can body diameter, is to be achieved during the cupping operation, which is a significant departure from prior practice. The invention enables such significant decrease in a single stroke cupping operation free of wrinkles in, or buckling of, the sheet metal can stock. At least about fifty and up to about ninety percent of that gross diameter-reduction, from cut blank diameter to final can body diameter, is accomplished during the cupping portion of the blanking and cupping operation of the present invention. Commercial blanking and cupping operations in the past have tended to slow operations in single action presses, or have required special handling of the cup- shaped work product for subsequent processing. One aspect of the invention is specifically concerned with decreasing stroke time by providing relative movement between cupping die and cupping punch during the cupping operation. The cupping operation (FIGS. 2-13) also avoids product drive- through and avoids any need to invert, or otherwise handle, the drawn cup prior to subsequent processing. Part of increasing production rate is accomplished by increasing rate of movement of the tooling after cup formation. Also, the drawn cup-shaped work product 37 is discharged directly onto the travel path of the fabricating line on its flange open-end-down as forming of cup 37 (FIG. 1) is completed. The cup-shaped work product 37, with side wall metal 38 between transition zone 39 at endwall 40 and flange metal 41 at its open end, travels open-end-down on flange metal 41 in the fabricating line travel path toward redraw station 42. Open-end-down fabrication continues in a single redraw press to produce shallow-depth can body 43, having an endwall 44 and side wall 45 extending between transition zone 46 and open end flange 47. Side wall thickness gage is prevented from increasing in the cupping operation. And in subsequent redraw operations, side wall thickness gage is decreased as a new container diameter is fabricated. Improved tension control for uniform tension elongation is provided as the new diameter is formed. That is, side wall height is increased while uniformly decreasing side wall thickness gage by controlled tension elongation, using method and means described later in more detail. Flat-rolled sheet metal of predetermined gage (and preferably of work-hardened characteristics) is produced at station 35 and precoated on both its surfaces with organic polymeric coating and lubricant. Such preparation and coating are preferably carried out on continuous strip; but cut sheet metal can be precoated and fed into new blanking and cupping press means 36. Can bodies are ready as draw-processed for direct use in canning comestibles without requirement for lubricant removal, cleansing-type treatment, organic coating, or adding of organic coating to the precoat. Can body finishing, as part of a fabricating line, includes endwall profiling (indicated schematically at 48) . In practice of the invention, endwall profiling is carried out as part of the two-step process at redraw press 42, or as part of a three-step process at second diameter reduction redraw station 49. That is, in production each final redraw press includes endwall profiling structure as an integral part of the redraw tooling, as shown and described in more detail later. Trimming of flange metal 47, or trimming of flange metal 50 of second redrawn can body 51, is carried out at station 52. An optional side wall profiling (for selected can bodies in which side. wall height exceeds can body diameter) is carried out at station 53 as flange trimming is completed. The can body is inspected at station 54, for example, for pin holes before canning at station 55. Use of the tooling means of FIGS. 2-8 in the blanking and cupping press means of FIGS. 11-13 increases the production rate for drawn sheet metal cup-shaped work product over that of previous commercial practice. Thus, operation of the overall can body fabricating line over a wider range of production rates is made practical so as to facilitate better coordination of can body fabrication with on-site canning operations. The organic polymeric coating applied to a surface- prepared sheet metal substrate embodies a "blooming compound"; that is, a lubricant which is activated by the heat and/or pressure of draw-processing fabrication. Pre- measurement of lube coating weight (blooming compound and added surface coating) is evaluated at station 35 for possible augmenting of lubricant by surface application to the can stock while in planar form. The precoated organic coating and draw lubricant (integral blooming compound and/or surface applied) are preselected, in particular for the internal (product side) surfaces of can bodies for comestibles, to meet requirements of governmental regulatory agencies such as the U.S. Food and Drug Administration and/or the U.S. Department of Agriculture. The blooming compound incorporated in the organic coating and/or surface-applied augmenting lubrication are selected for each surface. Total lubricant coating weight on each surface is preselected in the range of about 15 to 20 mg/sq. ft. Organic and lubricant requirements to meet fabricating stress on the external, or public-side, surface of the can body can differ from requirements on the internal, or product-side, surface. Copending and co-owned U.S. Patent Applications Serial No. 07/926,055 entitled COMPOSITE-COATED FLAT- ROLLED SHEET METAL MANUFACTURE AND PRODUCT, filed August 6, 1992 and Serial No. 08/047,451 entitled LIGHT-GAGE, COMPOSITE-COATED FLAT-ROLLED STEEL MANUFACTURE AND PRODUCT, filed April 19, 1993 are incorporated herein by reference for further details relating to surface preparation practices for preparing flat-rolled steel as a preferred substrate for organically coated can stock. Thermosetting organic polymeric coatings and draw lubricant materials approved by the U.S. Food and Drug Administration for use in canning comestibles are set forth in copending parent application Serial No. 07/866,661 which is incorporated herein by reference. The flat-rolled sheet metal substrate with a single reduced substrate having a starting gage of about fifty to about eighty-five lb/bb is preferred. Work-hardened sheet metal has advantages during the draw processing by diminishing change in substrate characteristics, for example. Double-reduced flat-rolled steel (see Making. Shaping and Treating Steel. 9th Ed., 1971, page 971 ©AISE, printed by Herbick & Held, Pittsburgh, PA) is used in thickness gages of about fifty to about seventy lb/bb and/or triple-reduced work-hardened steel described in copending parent Patent Application Serial No. 08/047,451 (which is included herein by reference) is used in starting gage from about thirty-six to about fifty lb/bb. The planar portion of the closed endwall 40 of cup 37 is at starting gage. A large curved-surface area punch nose is selected for forming the curved-surface unitary juncture 39 between endwall 40 and flange 41. The curved- surface area of the cupping punch nose corresponds to the curved-surface area of transition zone 39 of the cup- shaped work product; a large surface area punch nose is preselected to facilitate initiation of sheet metal movement. The major decrease in diameter (from blank to final can body diameter) is selected to be carried out in the blanking and cupping press. Above 50% to about 90% of the total diameter decrease, that is, from blank diameter size to the desired final can body diameter size takes place in the cupping operation. The initiation of movement of flat-rolled sheet metal from its planar configuration into a cylindrical configuration is facilitated by the predeterminedly large curved-surface area of the punch nose. The unitary juncture 39 of drawn cup 37 is drawn about a punch nose radius having a curved surface area as large as possible while avoiding buckling of the sheet metal. The punch nose curved surface area, as projected on a horizonal clamping plane and measured radially, exceeds thirty and extends up to about forty times nominal starting thickness gage for the can stock substrate. A large surface area, e.g., with about three-tenths inch projection as measured radially, for example, is used with sixty-five/bb (.0064" to .0079") double reduced flat-rolled steel. Forming the cavity entrance zone of the cupping draw die about as small a curved surface as practical, while avoiding tearing of the substrate, includes about one to about five times sheet metal gage as projected on a horizontal clamping plane. Such departures from conventional draw practice, along with preselected tooling clearance equal to can stock thickness, facilitate cup formation and eliminate any thickening of side wall metal during the cupping operation. In a more specific teaching of the invention, the draw die curved surface entrance zone is formed about multiple radii described in part in the copending parent Patent Application Serial No. 07/596,854 which is incorporated herein by reference, and is also described later herein. As part of new blanking and cupping teachings, the cup-shaped work product 40 is formed with open-end down and travels open-end-down on flange metal 41. In the can body fabricating system of the invention, such open-end- down travel on flange metal continues throughout draw- processing. Flange metal is oriented in a plane which is transverse (at or near perpendicular) to the central longitudinal axis of the cup-shaped work product. The latter axis is perpendicular to the geometric center of the circular configuration endwall of the work product. The flange metal around the full open end periphery is properly oriented to support the work product for travel in the fabricating line, and to prevent distortion of the cylindrical configuration at the open-end of the work product to facilitate proper feed into redraw apparatus. Solely planar clamping enables more uniform control of tension around full perimeter during the formation of a cup, and more uniform tension elongation is achieved in redraw-processing to produce substantially uniform side wall thickness gage throughout side wall height from closed end unitary curved surface transition zone to the flange metal at the open end of the can body. Referring to FIGS. 2-8 and FIGS. 11-13, the cupping die and cupping punch both move in relation to each other in a closing direction to form the cup; and, subsequently, both move in an opening direction in relation to each other to release and discharge the drawn cup-shaped work product, on its flange, for movement along the fabrication line travel path as new sheet metal advances into station 38 for blanking. That is, both the draw die and draw punch move rapidly away from each other to release the cup. The total length of cup forming stroke is effectively equal to side wall height; but the actual stroke time is signi icantly decreased in relation to the conventional draw apparatus operation, and the can stock incoming feed time is advanced and increased. Use of a rotary-drive crankshaft drive source, shown schematically at 56 in FIG. 9, driven, e.g., by an electric motor (not shown) , and acting through connector arm means 57, 58, enables predetermined selection of relative movement between cupping die 60 and cupping punch 62. By selection of out-of-phase (about 135°) motion for each, the timing can be more effective over a 360° cycle. The coacting cup forming stage of the cycle can be selected when the rate of movement of each tool is slower, which facilitates cup formation, and more rapid release of the formed cup takes place when each tool is moving at a faster rate. Movement of can stock into the press can be advanced to facilitate movement of the released cup from the press. The separate connecting arm means are selected for driving the cupping die and for driving the cupping punch, which are driven by a single rotary drive crankshaft means, as shown in FIG. 9. In FIG. 2, cupping die 60 is in its top dead center (TDC) position, and cupping punch 62 is moving downwardly in the direction indicated by arrow 63 away from die cavity 64. The clamping ring 65 is spring-loaded with planar clamping surface 66 in the travel path of the fabricating line; cutting edge 66 of blanking die 70 also is spring-loaded upwardly by clamping ring 65. The cupping die and cupping punch, as shown in FIGS. 2-13, are driven out-of-phase (by about 135°) by the crankshaft means and connector arm means. The relative movement between the die and punch decreases the cup forming time, releases the formed cup more rapidly, and increases the production rate of the press. Fast release of the formed cup provides for early movement of can stock into the press, and rapid discharge of the cup open-end- down onto the travel path of the system. Cupping die 60, at its top dead center (TDC) in FIG. 2, is at the start of a three hundred sixty degree cycle for rotary drive crankshaft means 56 of FIG. 9. At about 40° into that 360° cycle (FIG. 3) ; cupping die 60 is moving downwardly in the direction shown by arrow 73. Note that cupping punch 62, which had been moving downwardly in FIG. 2, reaches its bottom dead center (BDC) in FIG. 3. In the illustrated embodiment of the invention, the cupping die and cupping punch are moving about a hundred and fifty degrees out-of-phase. From about 40° to about 147° (FIG. 4) into the 360° cycle of rotary drive, cupping die 60 and cupping punch 62 are moving toward each other (in a closing direction) from opposite sides of fabricating travel plane 30. Punch 62 is moving toward the can stock surface which will constitute the interior (product side) of the work product; and punch 62 is moving in the direction of arrow 74 toward the exterior or public side of the cup, and the cup is to be drawn open-end-down. In FIG. 4, the can stock fed into the press is clamped between planar clamping surface 61 of cupping die 60 and the planar surface 66 of clamping ring 65. The latter is coaxial with cupping punch 62. The cupping die 60 has a cutting edge 75 at its outer periphery. Cutting edge 75 coacts cutting edge 68 with fixed blanking tool 70; cutting edge 68 is located at travel plane 30 at the fabricating line. A circular blank is cut as part of the blanking action of FIG. 4. In FIG. 5, the can stock is clamped between the above-described planar surfaces. Shaping of the cup-shaped work product from flat- rolled can stock is commenced (after blanking) with simultaneous, coaxial, overlapping relative movement between punch 62 and die 60 as indicated by arrows 73, 74 in FIG. 4. As can stock is drawn into die cavity 64, the cupping die 60 reaches its bottom dead center (BDC) , as shown in FIG. 5. In FIG. 6, punch and die are moved in the same direction with die 60 now moving in the upward direction shown by arrow 78, while both die and punch continue to move relative to each other in overlapping relationship. Cupping die 60 and punch 62 move coaxially in relation to centrally-located axis 85 (FIG. 6) ; such axis is perpendicular to the geometric center of the cup-shaped work product endwall, as well as being centrally located in relation to the symmetrically located tooling of FIGS. 2-8) . The crankshaft and connector arm means drive die 60 and punch 62 at selected value between about one hundred thirty-five and one hundred fifty degrees out-of- phase; the selected out-of-phase relationship having been maintained through the full cycle until cupping die 60 again reaches TDC. Note that the BDC status of punch 62 (FIG. 3) is 40° out-of-phase with the BDC of cupping die 60 (FIG. 5) . Such out-of-phase movement provides for differing rates of movement of the individual tools at differing cycle stages. Slower movement of the tooling, with increased force, takes place during the cup forming operation; and more rapid movement takes place after completion of cup formation for more rapid release of the cup and cup removal. Die 60 moves slowly after cutting the blank in approaching its BDC (shown in FIG. 5) and in starting its upward movement, while punch 62 continues to move upwardly at a faster rate than die 60 as formation of the cup is being completed. Cupping is completed as punch 62 reaches its TDC at 220° into the 360° cycle (FIG. 7) . As cup forming is completed, the tools move in opposite directions in relation to each other and release of the cup occurs rapidly. When both tools are free of the drawn cup, it is free to move from the press. Flat-rolled can stock has started to enter the press shortly before 293° into the cycle (FIG. 8) ; that is, shortly before the drawn cup is free to move from the press. During the time, from 293° into the cycle (FIG. 8) until slightly less that 147° into the next cycle, removal of the drawn cup is completed and introduction of can stock for the next cup is completed with the can stock in position for blanking. Such out-of-phase relationship during about half of the 360° cycle is shown by the apparatus in the several views of FIGS. 9-13. Clamping ring 65 is pre-loaded for limited movement to allow for blanking, and to provide selected clamping force by pneumatic cylinders (available from Teledyne- Hyson Company, Dearborn, MI) , or other preloaded spring- type structures can be used. Incoming non-blanked can stock, or other means, can be used to start movement of the cup from the press as punch 62 reaches the position shown in FIG. 8; both cupping die and punch provide clearance for cup travel. The movement of the non-blanked sheet metal in the plane of travel plane 30 can be started shortly prior to the disposition shown in FIG. 8, since the flat can stock can be moved in its longitudinal direction a distance equal to the radial dimension of the initially-clamped metal (FIG. 4) ; that is, prior to full retraction of the punch 62 to the disposition shown in FIG. 8. Such movement of the can stock can be relied on to start movement of the work product from the cupping station onto travel path 30, or mechanically or magnetically activated means in the travel path can be used for cup movement toward the first redraw station. FIGS. 9-14 schematically show rotational movement of crankshaft 56 by means of connector arm means 57, 58 which move cupping die and cupping punch through the positions shown in FIGS. 2-8. Portions of the cup forming tooling are shown in more detail in FIG. 14. Cup 42 is drawn symmetrically in relation to central longitudinal axis 80, free of any increase in side wall thickness gage, by selection of tooling dimensions and configurations, preselected uniform peripheral clearance between punch and die, and by planar clamping. Punch nose 82 is selected to have a surface area as projected on a horizontal plane, and measured radially, which is about forty times can stock thickness gage. Cavity entrance zone 84 is formed about multiple radii of curvature while maintaining a projection on the planar clamping surface which, measured radially, is about two to about five times can stock starting thickness gage. Use of multiple radii of curvature increases curved-surface area for start of movement of sheet metal into the cavity without increasing the projection of the entrance zone onto the clamping plane surface, while presenting a sharp edge for redrawing planar-oriented metal in multiple directions into a curvilinear side wall. In the specific embodiment, the multiple radii used for the cavity entrance zone 84 are about .05"/.02"/.05". The outer surface radius .05" provides for the gradual movement of can stock into and out of the transition zone, and mid- surface radius is about .02". The latter provides a sharper-edge configuration about which the can stock moves into the die cavity, which is an important aspect in achieving the uniformity of side wall gage; and the extent of gage reduction without breaking, tearing or cutting of sheet metal at such edges as metal is moved into a cylindrical configuration. Note that such middle radius (.02") is under tension about which metal is drawn into the cavity about two times sheet metal gage for seventy-five lb/bb flat-rolled steel can stock; while initiation of entrance movement into the transition zone has a radius of about five to seven times that gage. The clearance between punch 62 and interior wall 58 of cupping die 60 (around the full perimeter of each) is at least about the thickness of the coated can stock and can allow for tolerance specifications of the sheet metal. Also, cavity wall 88 is slightly tapered internally to provide increasing diameter with increasing depth of penetration into such cavity. In a later redraw stage or stage of a two-step process, or two redraw stages, tooling clearance is selectively decreased between punch and cavity in relation to metal gage being drawn into the cavity which results in an increased side wall height under tension elongation. The tension on the metal being drawn into the cavity is uniform about its perimeter due to plane clamping and is gradually increased. The clearance at the die side wall (after the redraw die cavity entrance zone) is slightly less than the gage of can stock as it enters the cavity transition zone for tension elongation. Such elongation starts in the transition zone and is controlled by selection of the clearance at the full diameter of both punch and die. Tension-elongation of the sheet metal during the redraw is maximized about such small mid-radius sharp angle of a redraw cavity entrance zone. Planar clamping pressure is maintained throughout forming of the redrawn cup. During redraw-processing of the invention, the uniform tooling clearance is selected around full side wall periphery to be equal to the gage of the can stock, not as introduced into the planar clamping area, but the gage of can stock as elongated about the cavity entrance transition zone for entry in a recessed internal side wall die cavity. The sheet metal is elongated under tension, free of ironing without being forged through a small diameter opening as used in side wall in ironing. The object in such redraw-processing, for a uniform redrawn side wall gage, is to set the clearances between redraw die and redraw punch less than the starting thickness gage for the coated can stock but equal to gage of the side wall as elongated through planar clamping and around the cavity entrance transition zone. The redraw gage reduction, for example, in the specific embodiment with a starting gage of .0072" double-reduced steel, a clearance of about .007" (measured radially in cross section) is provided around the circumference in a redraw cupping die to provide tension elongation around the cavity entrance zone resulting in a side wall gage of about .0066"; the decreased gage is substantially uniform throughout side wall height between the closed endwall juncture and the open end flange. In a three-step operation, the clearance is also preselected in the successive diameter-decrease redraw operation to provide a uniform side wall gage of about .0055" for such embodiment; a uniform decrease in side wall gage of slightly more than twenty percent. During the decrease in blank diameter of the cupping operation and subsequent decrease in cup diameter operation or operations, curved surface clampings or mating of any curved clamping surfaces, is eliminated; solely planar clamping provides uniform peripheral clamping and more accurate control of clamping pressure uniformly around the circumference. Redraw apparatus is shown in FIG. 14. However, the curved-surface cup juncture 39 between the closed endwall and side wall of the cup-shaped work product 37 is first reshaped about a smaller curved peripheral surface of the redraw clamping tool, as shown in FIGS. 16-18 and described in detail in copending application #07/866,661 which is incorporated herein by reference. The start of such juncture reshaping is carried out in a manner which creates a force on the closed endwall metal of the work product. That force is directed in a transverse plane in a direction away from the central longitudinal axis of the cup. The importance of such reshaping of the curved-surface work product juncture (as well as in the subsequent diameter-reduction redraw operation) is the same; reshaping such curved juncture, as taught, adds to the surface area of the can stock available solely for planar clamping between planar surfaces during formation .of the new diameter can body. Fabrication of the multiple radii transition zone of the clamping ring of FIGS. 15 and 16-19 is shown in FIG. 20 and, also, is described in detail in such incorporated parent application. FIG. 16 shows the juxtaposition of cup 42 with tooling approaching the closed endwall juncture 39 for such reshaping. Redraw die 102 (FIG. 15) presents solely planar clamping surface 103 and such planar clamping surface lies in a plane which is oriented to be transverse to central longitudinal axis 80. When redrawn dies are made from sinter-hardened machineable material, such as tungsten carbide; and the clamping surface area is extended, as shown in FIG. 16, a taper is provided between the planar clamping surfaces. For example, surface 103 can be tapered (opening outwardly) a fraction of a degree (such as 0° 5') to facilitate movement of the can stock along such surface toward the cavity; for further details on use of taper with sinter-hardened tooling, see assignee's copending application Serial No. 07/490,781 entitled DRAW-PROCESS METHODS, SYSTEMS AND TOOLING FOR FABRICATING ONE-PIECE CAN BODIES. Axially-movable clamping tool 104 has a sleeve-like configuration and is disposed to circumscribe redraw punch 106. The redraw punch is adapted to move can stock into cavity 108 as defined by redraw die 102. The clearance between the internal wall of redraw cavity 108 and the peripheral wall of punch 106 is selectively decreased for each redraw in relation to the starting gage. Radial- clearance about the redraw punch is about 5% to about 15% less than substrate thickness, but is selected to be approximately equal to, or slightly greater than, the gage of the side wall as elongated about sharp-edge cavity entrance zone. Elongation of the can stock starts with movement of the large redraw punch as metal is drawn around a sharp-edge mid-radius of a cavity entrance zone. By decreasing clearance for tensile elongated metal to enter the die cavity above the transition zone, tension in the side wall substrate is increased. The substrate is stretched, decreasing in thickness by elongation under tension about the sharp edge of the cavity entrance zone as the curved punch nose radius enters the die cavity. The result of that type of draw or redraw is a uniform decrease in side wall thickness gage along side wall height between juncture and flange of the redrawn can body. The redrawn side wall substrate gage is decreased about 10% to about 20% in the first redraw of FIG. 1. A combined side wall substrate thickness gage in the final and second redraws of FIG. 1 can be selected to provide a total gage reduction up to about twenty-five percent; total decrease can extend to about thirty-five percent; but the amount of decrease in side wall gage is dependent on starting gage and side wall requirements for sanitary can pack usage Referring to FIGS. 15-19, clamping sleeve 104 includes side wall 110, planar clamping endwall 111 and curved-surface transition zone 112 therebetween. The dimension of peripheral wall 110 of clamping sleeve 104 provides allowance for tool clearance (about .0025") in relation to the internal wall 38 internal side dimension of a work product cup 37. The surface area of transition zone 112 of clamping sleeve 104 is significantly smaller than one-half the surface area of juncture 39 of cup 34; for example, about one fourth to about one-half. That is, in a specific embodiment, a projection of the transition zone 112 onto 26 RECTIFIED SHEET ■ a clamping surface plane which is perpendicularly transverse to the central longitudinal axis occupies less than about 40% of the projection of cup juncture 101 on such plane. The interrelationship of these curved surfaces is selected to provide a difference of at least 60% in their radial projections on the transverse clamping plane. Juncture 37 of cup 37 is reshaped about transition zone 112 prior to otherwise starting metal movement into the die cavity due to movement of the redraw punch 106. Reshaping of the cup-shaped work product juncture is shown in FIGS. 12-15. A smaller redraw die cavity entrance zone surface (described in more detail in relation to later figures) also increases the planar clamping surface area of the redraw die for coaction with the planar surface of the redrawn clamping ring. The redraw die cavity entrance radial projection is from about five to about .5 times substrate gage in the sequence of operations. Combining the effect of reshaping the cup juncture and use of a smaller cavity entrance zone projection increases the planar clamping surface available by a factor of at least two over that available for corresponding can body sizes using conventional draw-redraw tooling. The redraw clamping sleeve peripheral transition zone (as viewed in cross section) is fabricated about multiple radii. As shown in FIG. 20, clamping sleeve 124 includes a planar endwall 126 which is transverse to the centerline axis of the cup; clamping sleeve 124 also includes a peripheral side wall 127. In preferred fabrication of the curved-surface transition zone for the clamping tool, a "large" radius R is used about center 128 to establish circular arc 129 which is tangent to the planar endwall surface 126. Extending circular arc 129 through 45° intersects with the extended plane of peripheral side wall 127 at imaginary point 130. Using the radius R about center 132 establishes circular arc 134 tangent to side wall 127; extending arc 134 through 45° intersects the transverse clamping plane of endwall 126 at imaginary point 136. Straight line 137 is drawn between imaginary point 136 and center 132; straight line 138 is drawn between imaginary point 130 and center 128; interrupted line 139 is drawn so as to be equidistant between parallel lines 137 and 138. Line 139 comprises the loci of points for the center of a "small" radius of curvature which will be tangent to both the circular arcs 129 and 134 so as to avoid an abrupt surface intersection at imaginary point 141. Using a radius of 1/2 R with its center 142 along line 139, circular arc 143 is drawn to complete a smooth, multiple radii curved surface for the transition zone of redraw clamping sleeve 124. As a result of the clamping tool design of FIG. 16, the projection of the multiple radii curved surface on the transverse clamping plane of endwall 111 is .0707 times R, resulting in a further increase of almost 30% in the planar clamping surface over that available if a single 28 RECTIFIED SHEET -' radius R were used for the curved surface transition zone of redraw clamping sleeve 124. Also, a more gradual curved entrance surface 144 into the transition zone is provided; and a more gradual curved surface 145 from the transition zone onto the clamping surface 126 is provided. Curved surface 144 also provides for easier entrance of the redraw clamping ring transition zone into contact with the internal surface of the curved juncture of a cup- shaped work product for such juncture reshaping step. In a specific cylindrical configuration embodiment for a multiple radii clamping sleeve transition zone for reshaping a .300" radius of curvature juncture for work product cup 76, R is selected to be .100"; therefore, the projection of clamping sleeve multiple radii transition zone on the transverse clamping plane comprises .0707", rounded off as .071". Other values for R can be selected; for example, a 1.25" radius of curvature for reshaping a cup juncture of substantially greater radius than .300"; or .9" for reshaping a smaller radius of curvature juncture; in general selecting R as .100" will provide desired results throughout the preferred commercial range of can sizes designated earlier. As shown in cross section in FIG. 15, a funnel-shaped configuration 146 is established between planar surface 103 of die 102 and clamping sleeve transition zone 112 for movement of work product can stock into the axially transverse clamping plane without damage to the coating as male punch 106 moves into cavity 108. A further relief can be provided by having surface 103 diverge away from the clamping plane, as described earlier, at a location which is external (in a direction away from axis 80) of the planar clamping surface. The can stock is stretched under tension by movement of the redraw punch of FIG. 15. Redraw punch 106 includes endwall 147, peripheral side wall 148 and curved surface transition zone 149 between such endwall and side wall. A large surface area is provided at transition zone 149 (the redraw punch nose) to the extent permitted by geometry requirements at the closed endwall juncture in later stages of the work product to facilitate starting each new diameter side wall. Coaction between such large surface area punch nose formed about a 0.20" radius of curvature for diameter reduction of the shallow-depth cup 37 in the specific example; also, a small projection cavity entrance zone surface is used, as described, preferably formed about multiple radii of curvature .050"/.020"/.050". Referring to FIGS. 21-23 regarding such multiple radii cavity entrance zone, FIG. 21 is a vertical cross- sectional partial view of a cavity entrance zone for die 165 formed about a single radius of curvature 166, selected in accordance with earlier presented teachings at about five times sheet metal starting gage for the cupping stage; such radius decreasing in subsequent redraw operations. Single radius curved surface 168 for the entrance cavity is spaced from central longitudinal axis 80 and extends symmetrically between planar clamping surface 171 and internal side wall surface 172. Curved surface 168 is tangential (as viewed in such cross section) at each end of its 90° arc; that is, tangential to planar surface 171 and to the cavity internal surface 172, respectively. In FIG. 22, such curved surface 168 (about single radius of curvature 173 of FIG. 22) is shown as an interrupted line; a 45° angle line 173, between the planar clamping surface and cavity side wall, is also shown by an interrupted line. Such 45° angle line 173 meets the respective points of tangency of single radius curved surface 168 with the planar clamping surface 171 at 174 and the internal side wall 172 at 175. The planar clamping surface 171 and the cavity internal surface 172 (as represented in cross section) would, if extended, define an included angle of 90°. A larger surface area 176 (FIG. 16) for the entrance zone is provided by the present invention. The multiple radii cavity entrance zone concept is carried out, in the specific embodiment being described, by selecting a radius of about .050" as the "larger" radius (RL) for the multiple radii surface. Placement of such larger radii (RL, FIG. 17) surface provides for the more gradual movement of can stock from the planar clamping surface into the cavity entrance zone and, also, for the more gradual movement from the entrance zone into the interior side wall of the cavity. A smaller radius (Rs) for the specific embodiment, selected at about .020", is used to establish a curved surface which is intermediate, such larger radius (RL) portions located at the arcuate ends of the entrance zone surface. That is, the Rs surface is centrally located of such entrance zone. The interior cavity wall 172 is recessed slightly, about one-half degree to about 1°, in progressing from the curved surface entrance zone into the cavity. A portion (181) of the curved surface 176 of FIG. 22 is formed in FIG. 23 about center 177 and uses the larger radius RL (.050"); such surface portion 178 is tangential to the planar clamping surface 171 of the draw die. Such larger radius is used about center 180 to provide curvilinear surface 181 leading into the internal side wall of the cavity. To derive the loci of points for the centrally located smaller radius (Rs) of curvature portion of the curved surface, the arcs of the larger radii surfaces 178, 181 are extended to establish an imaginary point 184 at their intersection. Connecting imaginary point 184 with midpoint 185 of an imaginary line 186 between the R centers 177, 180 provides the remaining point for establishing the loci of points (line 188) for the center of the smaller radius (Rs) of curvature; the latter will provide a curvilinear surface 190 which is tangential to both larger radius (RL) curvilinear surfaces 178 and 181. In the specific embodiment for a twelve ounce beverage can body, the larger radius (RL) of curvature is selected at about .05" (in a range of .040" to .060") and the smaller radius (Rs) of curvature is selected at about .02" (in the range of .015" to .025"). A specific example for the cupping cavity entrance zone is .025"/.010"/.025". In such multiple radii configurations, the smaller radius (Rs) curved surface is located intermediate the two larger (RL) surfaces, e.g. .05"/.02"/.05", and provides the edge about which the can stock is tensioned as the side wall is stretched for movement into the preselected clearance between the punch diameter and the start of the die cavity internal wall. In order to provide a 1° recessed taper (FIG. 23) for the die cavity internal surface, the arc between the planar clamping surface and such internal surface is increased by 1°; such 1° arc increase being added at the internal surface end of the arc. Such added 1° of arc enables such internal surface to be tangent to the curved surface at point 191; that is, 1° beyond the 90° point of tangency (175) . A tangential recess-tapered internal side wall cannot be provided without such added arc provision as described immediately above. The location of a 1° taper internal side wall surface, in a vertically oriented plane which includes the central longitudinal axis of the draw cavity, is shown at line 192 in relation to a non- tapered side wall surface indicated by line 172. Endwall profiling is carried out in the final redraw in either two-step or three-step processing, with endwall profiling tooling, as shown in FIGS. 24-25. The bottom wall 220 of the redrawn work product is reshaped using closed endwall profile tooling. As shown in FIG. 24, reshaping of the curved juncture of the previous cup has been completed and the metal which is peripheral to upwardly moving redraw punch 212 is being clamped solely between the planar clamping surface 213 of draw die 214 and upper planar surface 216 of clamping tool 217, free of curved nesting surfaces. A new diameter is being redrawn about the peripheral portion 218 of final redraw punch 212 so that endwall 220 is planar during this phase of the draw-processing. Male profile member 226 is fixed, so that coaction between its profiling surface 228 and the recessed profiling surface 230 of draw punch 212 is started as redraw is being completed. As shown in FIG. 25, clamping action has been released on flange 222 as draw die 214 moves upwardly. As clamping action is released, final redraw punch 212 approaches and reaches the top of its upward stroke to bring about countersinking of the endwall 20 (FIG. 22) to form the profiled endwall. The prior release of clamping action on the flange avoids damage to the sheet metal due to such movement. Final redraw punch 212 is withdrawn downwardly upon completion of endwall profiling. Such endwall profiling is described in copending Application Serial No. 07/866,661 which is incorporated herein by reference. 34 RECTIFIED SHEET Flat-rolled sheet metal for the can body application taught by the present invention can comprise flat-rolled steel from about thirty-six lb/bb to about eighty-five lb/bb in which thickness tolerances are generally within 10%; and nominal flat-rolled aluminum thickness gages are above about .005" to about .015". The preferred substrate surface for flat-rolled steel for adhesion of organic coating is a "TFS" (tin-free steel) coating which comprises an electrolytic plating of chrome and chrome oxide. However, with the present invention, deep drawing of flat-rolled steel with other substrate surfaces for later protective organic coating, such as chrome oxide from a bath or cathodic dichromate (CDC) treatment, or as disclosed in copending Application Serial No. 07/926,055 entitled COMPOSITE-COATED FLAT- ROLLED SHEET METAL MANUFACTURE AND PRODUCT, filed August 6, 1992 can also be utilized to augment surface adhesion of outer surface organic coating. Organic coating and draw lubricant coating are selected for each surface to provide for draw requirements on each such surface as well as container content requirements on the product side surface. That is, the types of organic coating and blooming compound draw lubricant are selected for a particular surface of the can stock. An organic coating weight for the "public" surface in the range of about two and one-half milligrams per square inch (2.5 mg/sq. in.) to about ten mg/sq. in. is preferred on the "product side." Thermosetting organic coatings are preferably selected from epoxies, vinyls, organosols, acrylics, polyesters and films such as polyurethane, polypropelene, polyethylene and poly alkaline terephthaltes for use with containers for comestibles. The ability to manufacture draw-processed can bodies, including can bodies in which side wall height exceeds diameter, without damage to precoated organic polymeric coatings is an important contribution of the invention. A wide and increasing range or organic polymer coatings is finding use in canmaking. The organic coating is designated to withstand deep drawing as die wall metal is drawn, under tension, so as to avoid any significant increase in thickness gage along the side wall height. The organic coatings are selected so as to be capable of being applied with appropriate "blooming compound" draw lubricant, to meet particular surface requirements. The higher organic coating weight on the product side is utilized to assure product protection; the lubricant requirement on the product side surface is less than on the exterior. Suitable organic coatings with blooming compound for carrying out draw processing objectives of the invention are made available based on the product and can body size requirements through such coating manufacturers as The Valspar Corporation, 2000 Westhall Street, Pittsburgh, PA 15233, The Dexter Corporation, East Water Street, Waukegan, IL 60085, or BASF Corporation of Clifton, NJ. Any surface-applied draw lubricant required is added upon curing of the organic coating, with total draw lubricant (blooming compound and surface-applied) per side being selected in the range of about ten to about twenty mg per square foot per side. Surface lubrication is preferably carried out after curing of the organic coating by coil coaters such as Precoat Finish of St. Louis, MO, or PMP of McKeesport, PA to enable demand oriented operation of the can body fabricating line, independent of surface preparation, as described earlier. Such desired draw lubricant coating weights on each surface are verified before entry of can stock into the fabricating process. With present teachings, the integrity of the precoated organic coating is maintained such that neither post- fabrication interior surface coating nor coating added for repair purposes is required for can bodies for sanitary can packs. Data on a specific embodiment of a two-step and three-step process, with comparison to conventional draw- redraw process is set forth below: TABLE I Two-Step Process Can Body for 307x110.5602 Pet Food Can (In Inches) Flat-Rolled Redrawn Steel Blank Cup Can Body bb per 1000 Metal Process Diameter Dia. |Hgt. Dia. |Hεt. Can Bodies Saving Conv. Draw Redraw 5.96 4.11 | 1.13 3.2 1 1.73 1.012 Base 2-Step (1 Redraw) Side Wall Gage Decrease 20% 5.73 3.541 1.44 3.291 1.73 .935 7.6% Three-Steπ Process Can Body for 211x315 10-3/4 oz. Soup Can (In Inches) Blank Cup 1st Redraw 2nd Redraw bb/1000 Metal Process Diameter Dia. |Hgt. Dia. l Hgt. Dia. | Hgt. Can Bodies Saving Conv.Draw Redraw 7.00 4.0212.04 3.14|.3.13 2.5714.01 1.40 Base 3-Step Side Wall Gage Decrease 18% 6.68 3.81 | 1.93 2.86 | 3.13 2.5714.01 1.25 10.8% 3-Step Side Wall Gage Decrease 20 % 6.57 3.811 1,88 2.8613.06 2.5714.01 1.23 12.5% While specific can body and can sizes, tooling dimensions, sheet metal materials and coating specifications have been set forth in describing the invention, those skilled in the art will recognize that modifications to such specific data and information can be utilized in light of the above teachings. Therefore, for purposes of determining the scope of the present invention, reference shall be had to the appended claims.

Claims: CLAIMS 1. Cup forming tooling for draw-processing precoated planar can stock into a precoated one-piece cylindrical-configuration shallow-depth cup-shaped work product, comprising, in combination, means for supplying circular-configuration cut blanks of can stock comprising flat-rolled sheet metal substrate of preselected starting gage which has been prepared for and precoated on both planar surfaces with organic polymeric coating and draw-processing lubricant; cupping press means with tooling means for (a) draw forming the precoated cut blank, free of side wall ironing, to form a one-piece cup-shaped work product having: (i) a substantially-planar closed endwall of circular configuration in plan view, (ii) a centrally-located axis (central longitudinal axis) in perpendicular relationship to the geometric center of the circular endwall, (Hi) a cylindrical-configuration side wall which is symmetrically disposed with respect to, and uniformly spaced from, the centrally-located axis, (iv) a unitary juncture between the planar endwall and cylindrical side wall, the unitary juncture having a curved configuration as viewed in cross section in a plane which includes the centrally-located axis, (v) a can stock flange extending around substantially the full perimeter at the open end of the cup-shaped work product as drawn, the flange being oriented in a plane in transverse relationship to the centrally-located axis so as to provide a uniform side wall height between such open end flange and the unitary juncture of the cup-shaped work product, with (vi) substrate of the closed endwall, between its geometric center and the unitary juncture, having a thickness gage substantially equal to the preselected starting gage for the flat- rolled sheet metal substrate as supplied, and (vii) side wall substrate which is free of an increase in thickness gage above such preselected starting gage throughout the height of the side wall from a location contiguous to the unitary juncture to a location contiguous to the flange at the open end of the cup-shaped work product; the draw forming tooling means being disposed for movement in coaxial relationship to the central longitudinal axis of the cup-shaped work product being formed, including (b) a cupping die presenting: (i) a centrally-located internal wall defining a die cavity having a circular configuration in a plane which is perpendicularly transverse to such central longitudinal axis, (ii) an entrance zone into such die cavity having a curvilinear configuration surface as viewed in cross section in a radial plane which includes such central longitudinal axis, (Hi) a planar clamping surface circumscribing the cavity entrance zone in transverse relationship to such central longitudinal axis; (c) a cupping punch presenting: (i) an endwall for forming a planar work product endwall which is disposed in perpendicularly-transverse relationship to such central longitudinal axis for the cup-shaped work product, (ii) a cylindrical side wall, and (Hi) a unitary juncture between such punch and side wall having a curvilinear configuration surface as viewed in cross section in a radial plane which includes such central longitudinal axis, the cupping punch being disposed for coaxial linear relative movement into, and from, the cupping die cavity along the centrally- located axis; and 80 (d) a clamping element circumscribing the cupping 81 punch, the clamping element presenting: 82 (i) a planar clamping surface in transverse 83 relationship to such central longitudinal axis 84 for coacting with the planar clamping surface of 85 the cupping die, and 86 (ϋ) a cylindrical side wall configuration 87 circumscribing the cupping punch; with 88 (e) the cupping die curvilinear cavity entrance zone 89 surface having a radial dimension as projected onto 90 a planar clamping surface perpendicular to such 91 central longitudinal axis, in a range which exceeds 92 such predetermined starting gage but is not 93 substantially greater than about five times such 94 starting gage, and 95 (f) the cupping punch curvilinear surface as 96 projected onto such planar clamping surface has a 97 radial dimension in a range which exceeds twenty-five 98 times such predetermined can stock thickness gage and 99 extends to abut forty times such gage. 1 2. The cup forming tooling of Claim 1, in which 2 the cupping die cavity entrance zone curvilinear 3 surface projected onto such planar clamping surface has a 4 radial dimension in the range of about .02" to about .05". 1 3. The cup forming tooling of Claim 2, in which 2 the curvilinear cavity entrance zone surface is 3 formed about multiple radii in which the radius: in entering such curvilinear surface from the cupping die planar clamping surface is about .05", in leaving such curvilinear surface for entry with the internal wall defining the die cavity is about .05", and as located therebetween is about .02". 4. The cupping tooling of Claim 3, in which the internal wall of such die cavity has a taper of about one degree as viewed in a radial plane which includes such central longitudinal axis, with such taper increasing the diameter of such internal wall with increasing penetration of such die cavity. 5. Fabricating line apparatus for draw-processing precoated planar can stock, free of side wall ironing, into precoated one-piece cylindrical-configuration shallow-depth cup-shaped work product, comprising, in combination, means establishing a travel plane for a fabricating line for feeding extended-length substantially-planar can stock in the direction of its length into the fabricating line; can stock supply means for the fabricating line for introducing flat-rolled sheet metal substrate of preselected starting gage which, independently of the fabricating line, has been prepared for and precoated on both planar surfaces with organic polymeric coating and draw-processing lubricant; a single station blanking and cupping press means with tooling means for (a) cutting a blank of predetermined diameter from the precoated planar can stock as introduced into the press means, and (b) draw forming the blank as cut to form a one- piece cup-shaped work product having: (i) a substantially-planar closed endwall of circular configuration in plan view, (ii) a centrally-located axis in perpendicular relationship to the geometric center of the circular endwall, ( ϋ) a cylindrical-configuration side wall which is symmetrically disposed with respect to, and uniformly spaced from, the centrally-located axis, (iv) a unitary juncture between the planar endwall and cylindrical side wall, the unitary juncture having a curved configuration as viewed in cross section in a plane which includes the centrally-located axis, (v) a can stock flange extending around substantially the full perimeter at the open end of the cup-shaped work product as drawn, the flange being oriented in a plane in transverse relationship to the centrally-located axis so as to provide a uniform side wall height between such open end flange and the unitary juncture of the cup-shaped work product, with (vi) substrate of the closed endwall, between its geometric center and the unitary juncture, having a thickness gage substantially equal to the preselected starting gage for the flat- rolled sheet metal substrate as supplied, and (vii) side wall substrate which is free of an increase in thickness gage above such preselected starting gage throughout the height of the side wall from a location contiguous to the unitary juncture to a location contiguous to the flange at the open end of the cup-shaped work product; the draw forming tooling means being disposed for movement in coaxial relationship to the central longitudinal axis of the cup-shaped work product being formed, including (c) a cupping die presenting: (i) a centrally-located internal wall defining a die cavity having a circular configuration in a plane which is perpendicularly transverse to such central longitudinal axis, (ii) an entrance zone into such die cavity having a curvilinear configuration surface as viewed in cross section in a radial plane which includes such central longitudinal axis, (Hi) a planar clamping surface circumscribing the cavity entrance zone in transverse relationship to such central longitudinal axis; (d) a cupping punch presenting: (i) an endwall for forming a planar work product endwall which is disposed in perpendicularly-transverse relationship to such central longitudinal axis for the cup-shaped work product, (ii) a cylindrical side wall, and (Hi) a unitary juncture having a curvilinear configuration as viewed in cross section in a radial plane which includes such central longitudinal axis, the cupping punch being disposed for coaxial linear relative movement into, and from, the cupping die cavity along the centrally- located axis; and (e) a clamping element circumscribing the cupping punch, the clamping element presenting: (i) a planar clamping surface in transverse relationship to such central longitudinal axis for coacting with the planar clamping surface of the cupping die, and (ii) a cylindrical side wall configuration circumscribing the cupping punch; with 96 (f) the cupping die cavity and planar clamping 97 surface of the cupping die confronting one surface of 98 can stock when located for draw-processing, and 99 (g) the endwall of the cupping punch and the planar 100 surface of the clamping element each confronting the 101 remaining surface of such can stock when so located, 102 with 103 (h) the planar clamping surface of the cupping die 104 and the planar clamping surface of the clamping 105 element contacting opposite surfaces of the precoated 106 can stock as the blank is cut so as to initiate 107 planar clamping of a peripheral portion of the cut 108 blank; 109 (i) the press means further including 110 (i) rotary drive crankshaft means operable 111 through a 360° drive cycle for each completion 112 of a fabricating cycle for a cup-shaped work 113 product, and 114 (ii) connector means, driven by the crankshaft 115 means, for separately driving the cupping die 116 and separately driving the cupping punch, with 117 the cupping die drive being predeterminedly out- 118 of-phase with the cupping punch drive throughout 119 the 360° rotary drive cycle of the crankshaft 120 means; 121 (j) the cupping die connector means and the cupping 122 punch connector means, as driven by the crankshaft 123 means, simultaneously driving such die and such punch 124 toward each other into coaxially-overlapping 125 relationship, from opposite surfaces of the coated 126 can stock, to initiate forming of the coated blank 127 into the cup-shaped product, and 128 simultaneously driving such die and such punch 129 moving away from each other, after completing forming 130 of the cup-shaped work product, in a manner: 131 (i) to expedite discharge of the cup-shaped 132 work product directly onto the travel plane for 133 movement in the fabricating line, 134 (ii) to enable initiation of movement of the 135 coated can stock along the travel plane into the 136 blanking and cupping press means for forming a 137 subsequent work product prior to completion of 138 withdrawal of the cupping punch from the 139 previously formed work product, and 140 (Hi) to enable continuing movement of precoated 141 planar can stock into the press means during a 142 predetermined percentage of the rotary drive 143 cycle of the crankshaft means after discharge of 144 such formed work product until the cupping die 145 and the cupping punch have each returned to the 146 travel plane from opposite sides of the can 147 stock to be in position to initiate forming of 148 a subsequent cup-shaped work product. 1 6. The apparatus of Claim 5, in which the can stock supply means introduces work-hardened flat-rolled steel precoated on both surfaces with organic polymeric coating and draw lubricant, and the separate connector means for the cupping die and for cupping punch are in a range between about 130° to about 150° out-of-phase throughout such fabricating cycle. 7. The apparatus of Claim 5, in which the crankshaft rotates through about 150° of a complete fabricating cycle after discharge of such formed work product during which planar can stock can be moved into the press means before the cupping die and cupping punch are in position to initiate forming of such subsequent work product so as to temporarily prevent movement of can stock into the fabricating press. 8. The apparatus of Claim 5, in which the respective connector means drive the cupping die and cupping punch in opposite directions in relation to each other, after forming of such cup-shaped work product, to discharge the cup-shaped work product on its flange, with its open end down, onto the travel plane of the fabricating line. 9. The apparatus of Claim 5, in which the respective connector means drive the cupping die and cupping punch in out-of-phase relationship causing the punch to reach bottom dead center of its movement below the travel plane of the fabricating line subsequent to the cupping die reaching top dead center of its movement above such travel plane; such out-of-phase drive" by respective connector means driving the cupping die and cupping punch in the same direction above such travel plane at a preselected rate of movement during a portion of the forming of the cup-shaped work product, and then driving the cupping punch and the cupping die at an increased rate of movement in opposite directions in relation to each other, after completion of forming of the cup-shaped work product so as to discharge the cup-shaped work product, as drawn by the blanking and cupping press means, prior to completion of a 360° rotary drive cycle of the crankshaft means from the initiation of cup-formation of such cycle during which planar can stock can be introduced into such press along the travel plane of the fabricating line. 10. The apparatus of Claim 6, in which the cupping die has a sleeve-like configuration with an inner cavity wall and an outer surface wall, each being of circular configuration in a plane which is perpendicularly transverse to such centrally located axis, with the outer surface wall presenting a cutting edge at its periphery in the planar clamping surface of the cupping die, the cutting edge having a predetermined diameter equal to the diameter preselected for the cut blank, and in which the planar clamping surface of the cupping die and the planar clamping surface of the clamping ring coact to clamp opposite surfaces of the precoated sheet metal cut blank about such peripheral portion of the cut blank solely between planar clamping surfaces; such coaction of the planar clamping surfaces continues through about 120° of the complete 360° crankshaft fabricating cycle during which the cupping die and cupping punch initially move in opposite directions and then in the same direction while remaining in overlapping coaxial relationship during such cup-forming portion of the crankshaft drive, with the side wall substrate of the cup-shaped work product being placed under substantially uniform tension by such planar clamping surfaces around said peripheral portion of the blank so as to prevent thickening of side wall sheet metal during forming of such cup-shaped work product. 11. The apparatus of claim 10, in which the can stock supply means introduces flat-rolled steel of a gage between about thirty-six to about seventy- five lb/bb precoated on both surfaces with organic polymeric coating and draw lubricant, and the decrease in preselected cut blank diameter carried out in such blanking and cupping press to form the cup-shaped work product is between about 35% to about 50% of such cut blank diameter. 12. The apparatus of claim 11, in which the cavity entrance zone between the planar clamping surface of the die and the inner side wall cavity of the die is formed about multiple radii to enable more gradual movement of the precoated sheet metal from its planar configuration into such entrance and from such entrance zone into its curvilinear side wall configuration, with the dimension of cavity entrance zone, as projected onto the travel plane of the fabricating line, being in a range exceeding the starting gage of the flat-rolled sheet metal substrate but not exceeding about five times such starting gage, and in which the cupping punch presents an endwall surface and a cylindrical side wall surface with a transition zone therebetween which is curvilinear as viewed in cross section in a plane which includes such central longitudinal axis, with the dimension of the curvilinear transition zone of the cupping punch has a dimension, as projected onto the travel plane for the fabricating line, in the range of about twenty-five to about forty times starting gage for such sheet metal substrate. 13. The apparatus of Claim 1 or 12, further including redraw press means located for receiving such cup- shaped work product and decreasing its side wall diameter tension elongation of side wall metal in order to increase its side wall height, such redraw press means including redraw tooling for relative movement of a redraw punch means into a redraw die means with such drawn cup- shaped work product therebetween; such relative movement between redraw punch and redraw die means forming a one-piece can body of decreased side wall diameter and increased side wall height, with can stock flange on its open end; with such redrawn can body side wall thickness gage being decreased uniformly in the range of about 10% to about 25% by such relative movement redraw punch means and into such die means. 14. Method for producing a precoated cylindrical configuration can body, ready as fabricated, for sanitary can packing of comestibles, comprising providing apparatus as set forth in claim 1 or 5, supplying work-hardened flat rolled sheet metal precoated on both its surfaces with organic polymeric coating and draw lubricant, drawing a cut blank of preselected diameter to produce a cylindrical side wall configuration cup-shaped work product in which at least about fifty percent to about ninety percent of the decrease in diameter from cut blank diameter to final can body diameter is carried out, as part of drawing such cup-shaped work product, without substantial increase in side wall thickness gage, and redrawing such cup-shaped work product to decrease its diameter so as to increase its side wall height to further increase side wall height, under tension, to decrease side wall thickness gage substantially uniformly over side wall height in a range between about 10% and about 25%. 15. Method for producing a precoated cylindrical configured one-piece can body with flange metal at its open end, ready as fabricated, for sanitary can packing of comestibles, comprising providing apparatus as set forth in Claim 1 or 5, supplying work-hardened flat-rolled steel having a thickness gage in the range of about 35 to about 70 lb/bb precoated on both its surfaces with an organic polymeric coating and draw lubricant, drawing a cut blank of preselected diameter from such can stock and forming a cup-shaped work product, with such cut blank diameter being decreased to form a cup-shaped work product with a cylindrical side wall diameter which is within a range between about 50% to about 35% of such cut blank diameter, and redrawing such cup-shaped work product in redraw press means to decrease its side wall diameter in a range between about 10% and about 30% to produce a finished can body, with such can body redrawing being carried out with uniform tension around such side wall to decrease side wall thickness gage by tension elongation uniformly over such redrawn can body side wall height within a range of about 10% to about 25% of starting gage for such precoated can stock. 16. A precoated one-piece cylindrical can body draw- processed, free of any side wall ironing, from precoated planar can stock and ready for use, as fabricated, in sanitary can packs, comprising (a) a substantially-planar closed endwall of circular configuration in plan view, (b) a centrally-located axis in perpendicular relationship to the geometric center of the circular endwall, (c) a cylindrical-configuration side wall which is symmetrically disposed with respect to, and uniformly spaced from, the centrally-located axis, (d) a unitary juncture between the planar endwall and cylindrical side wall, the unitary juncture having a curved configuration as viewed in cross section in a plane which includes the centrally- located axis, (e) a can stock flange extending around the full perimeter at the open end of the cup-shaped work product as drawn, the flange being oriented in a plane in transverse relationship to the centrally- located axis so as to provide a uniform side wall height between such open end flange and the unitary juncture of the cup-shaped work product, with (f) substrate of the closed endwall, between its geometric center and the unitary juncture, having a thickness gage substantially equal to the preselected starting gage for the flat-rolled sheet metal substrate as supplied, and (g) side wall substrate having a substantially uniform thickness gage throughout side wall height from a location contiguous to the unitary juncture to a location contiguous to the flange at the open end of the can body, which is in the range of about 10% to about 25% of such preselected starting gage. 17.. The fabricated precoated one-piece can body of Claim 16, in which such precoated can stock consists essentially of flat-rolled steel substrate having a starting thickness gage in the range of about thirty-five lb/bb to about eighty lb/bb; such substrate being precoated on both surfaces with a polymeric coating material and draw lubricant before fabricating. 18. The precoated as fabricated one-piece can body of Claim 16, in which end wall diameter exceeds side wall height, and in which such flat-rolled steel substrate is work-hardened prior to draw-processing and has a gage between about 35 and about 65 lb/bb; such organic coating consists essentially of a thermosetting organic polymeric material which has been cured prior to draw-processing, and such drawn lubricant comprises an organic material acceptable for canning comestibles. 19. A one-piece cylindrical-configuration precoated metal-substrate can body for sanitary can packs fabricated in symmetrical relationship to a central longitudinal axis by draw processing flat-rolled sheet metal substrate precoated with an organic coating and draw lubricant; such can body as fabricated, comprising: a closed endwall, a side wall extending in symmetrical relationship with the central longitudinal axis of the can body to define an open end for such can body, a unitary curved-surface transition zone between such endwall and side wall, and a flange extending outwardly with respect to such central longitudinal axis at such open end in a plane which is substantially perpendicularly transverse to such central longitudinal axis; such can body being fabricated free of any side wall ironing step; such fabricated can body presenting: an organic coating on its public side and its product side, with the organic coating on its product-side surface enabling direct use of the can body in canning comestibles free of any requirement for washing, for applying organic coating, or for adding organic coating for repair of such product-side surface, and in which the endwall metal substrate gage is substantially equal to starting thickness for such substrate, with such can body side wall having a substantially uniform thickness gage between such unitary transition zone and open end flange which is between about ten to about twenty-five percent less than starting gage. 20. The can body of claim 19 in which the flat- rolled sheet metal substrate comprises flat-rolled steel having a starting thickness gage in the range of about fifty to about eighty-five lb/bb. 21. The can body of claim 19 in which the flat- rolled sheet metal substrate comprises work-hardened flat-rolled steel having a starting gage in the range of about thirty-six to about seventy lb/bb.

Inventors: DALRYMPLE WILLIAM H, SAUNDERS WILLIAM T DI, DALRYMPLE, WILLIAM, H., SAUNDERS, WILLIAM, T. +DI
Applicants: WEIRTON STEEL CORP, WEIRTON STEEL CORPORATION
Application year: 1994
Main classification: B21D22
IPC codes: B21D22, B21D51